Question about 1999 Jeep Grand Cherokee

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Where are the spark plugs on a 99 cherokee 4.0? are they going to be a pain to change?

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  • yadayada
    yadayada Oct 17, 2010

    Yes the plugs are some what of a pain to change, the plugs are each fired by their own individual coil which is part of the coil rack assembly, remove the coil rack and the plugs are below it, they are 5/8" Below is a picture of the coil rack assembly.



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  • 5,332 Answers

They are on the passenger side of the engine, in the head, and under the spark plug wire boots. There are six of them.

You'll need a 3/8 ratchet, an extension, and a spark plug socket. A spark plug socket will have a rubber boot inside of it to protect the spark plug when removing and installing.

Remove the spark plug wires from the the plugs one at a time. Replace the plug, reinstall the plug wire, and then do the next one. This way you don't get the plug wires confused.

When installing the new plug make sure you start it buy hand and turn it several times into the cylinder to make sure the threads are not cross threads. Then use the ratchet and socket to tighten the rest of the way. They don't need to be super tight, just snug!

Make sure you use the correct champion plug. This is the same plug that was installed from the factory and the engine will run the best with this plug installed. they will be available from any parts store.

Good luck!

Posted on Oct 17, 2010


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